Halo 2 Walkthrough
Authorized Personnel Only
Fight through some more enemies and out into a shipping area. "They've reached the fire control center" you're told. Go through the door - checkpoint.

This is quick. Hit the door opener - checkpoint.

Now tons of wasp guys come in after you - shoot them down. These are the drones. After you take those out, another group of land troops will come after you. When you're clear - checkpoint - "concentrate fire on first carrier"

Now you're in another area with a massive elevator area and a turret. You hear that the first carrier ignored us and headed straight for earth.